Time for reconing?

[bowtie427ss]

846B should have the better "open" style N800-8K network.

FWIW, a friend recently disemboweled an old N800F and tested each component. Everything was within 5% of rated value. Says quite a bit for those old ELPAC caps after 30+ years in Arizona heat.

<font size="2" face="Verdana, Helvetica, sans-serif">This doesn't surprise me as i've gone thru altec networks that i expected to be way off and found the same result. And, i've also tested others and found caps that have drifted grossly in both directions, an 8mfd cap that measured almost 40mfd and a 21mfd cap that measured below 2mfd, and in one case found a shunt across the woofer circuit that was open.

I always measure them now, it's much cheaper than a new phragm.

I'm no expert here , but could the OP's complaint/observation be a result of damping ability/inability of his amplifiers?

My thought is that the 846B was probably designed/aimed more for solid state amplification that would provide electrical damping that isn't possible with his tube amplifiers..... just a thought.

Maybe a simple retuning of his enclosures to provide more acoustic damping for the woofers is all that's required.

................. just sharing some thoughts.

[bfish]

My thoughts exactly, bowtie, hence the suggestion to try swapping output taps.

Tube amps generally have signifigant output impedance, which reduces their abilty to control LF inertia-induced over-excursion (electrical damping). While there are applications where this can be used to advantage, providing tight, accurate bass in a minimally damped (mechanically) BR enclosure with a high compliance woofer isn't one of them.

I'm not saying the drivers don't need restored, just trying to eliminate the other possibilities so you don't spend the $ reconing drivers, only to find you still have the problem after doing so.

The easy way to see if this is the problem (after trying the output tap swap) is to substitute a SS amp, or temporarily seal off the cab ports with some plumbers test plugs (or old T-shirts).

<font color="#FFFFFF" size="1">[ December 07, 2007 03:14 PM: Message edited by: bfish ]</font>